Effect of Coupling Indium Tin Oxide with the TiO2–NaYF4:(Gd, Si) Composite for Photocatalytic Properties

Abstract

Indium tin oxide (ITO) nanoparticles were coupled with NaYF4:(Gd, Si) using a TiO2-solution impregnation method. Scanning electron microscopy confirmed that TiO2 and ITO nanoparticles were loaded on the surface of the NaYF4:(Gd, Si) upconversion phosphor. The ultraviolet/visible spectra of the 20 wt.% ITO-NaYF4:(Gd, Si)/TiO2 composites were extended at the absorption edges towards the UV-visible region. The 20 wt.% ITO-coupled NaYF4:(Gd, Si)/TiO2 composites exhibited superior photocatalytic efficiency compared to only NaYF4:(Gd, Si)/TiO2 under near-infrared (NIR) irradiation. Multi-wavelength NIR photons of γ > 760 nm from a Xe solar simulator source induced photo-activation through the NaYF4:(Gd, Si) activator centers. The three-cycle photocatalytic reusability performance of the 20 wt.% ITO-impregnated NaYF4:(Gd, Si)/TiO2 composite was positively enhanced by up to 20% more than that of NaYF4:(Gd, Si)/TiO2.